The Animal Resources Core will provide a centralized management for all research projects utilizing rats. This Core will be responsible for ordering and care of rats, all procedures administered to rats, tissue preparation, allocation and storage, mammary gland transplantations and injections, intraduct injections and monitor and maintenance of transgenic rats. The Core will provide quality control and uniformity of all animal- related procedures which will yield a significant savings and uniform results. The Core will be headed by Dr. Susanne Krnacik and assisted by Dr. Daniel Medina.